Recently, Thomas Kane wrote something very stupid about teacher ratings: he’s part of the chorus, led by New York governor Andrew Cuomo, that claims too many teachers are rated “effective”. Kane:

The fact that 96% of teachers were given the two highest ratings last year — being deemed either “effective” or “highly effective” — is a sure sign that principals have not been honest to date. An external perspective will make it easier for longtime colleagues to have a frank conversation about each other’s instruction.

The argument by Cuomo et alia has been that principals are using the non-test related portions of teacher evaluations to retain unqualified teachers. In other words, if we only used the tests, or weighted them much more strongly, then principals wouldn’t be able to protect the shirkers who hate America poorly-performing teachers. Fortunately, Jersey Jazzman evaluates that claim by looking at only the “growth measures”–the test-derived portion of a teacher’s assessment (boldface mine):

Let me go back to the latest NYS Technical Report for Growth Measures. Here’s page 43:

According to the report, 5 percent of New York’s “tested” teachers were found to be either “Developing” or “Ineffective” two years in a row on the state’s growth rating. It seems to me that this is very reasonably aligned with a 4 percent of teachers getting an overall rating of lower than “Effective.”

I mean, this is the whole point of Kane’s vaunted “multiple measures,” right? That we didn’t want to hurt the profession by letting statistical noise dictate decisions? That we should have a pattern of poor performance before we make a high-stakes decision, and it should be corroborated by multiple assessments of a teacher’s performance?